import java.io.*;
import java.util.HashMap;
import java.util.Map;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

/**
 * Created by admin on 2017/12/30.
 */
public class Test {
        public static void main(String[] args) {


            Map<String,Integer> map=new HashMap<>();
            String stuNo="";
            //字符流方式读文件
            String path="F:\\names.txt";
            BufferedReader reader=null;
            try {
                reader=new BufferedReader(new FileReader(path));

                while ((stuNo=reader.readLine())!=null){
                    map.put(stuNo,0);

                }
            } catch (FileNotFoundException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            }finally {
                try {
                    reader.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }


            File file=new File("F:\\16信本2班Java作业一");

            File[] files=file.listFiles();

            //遍历每一个文件

            for (File f:files){
                String fileName=f.getName();

                //保存提取到的学号
                String no="";


                //从文件夹中提取学号
                //正则表达式：1模板，2三个填空
                Matcher matcher= Pattern.compile("信本2班(\\d+)").matcher(fileName);

                while (matcher.find()){

                    no= matcher.group(1);
                }

                map.put(no,1);
            }

            //把value为0的打印出来
            //遍历一个map

            for (Map.Entry<String,Integer>entry:map.entrySet()){

                if (entry.getValue()==0){

                    System.out.println(entry.getKey());
                }
            }
        }
    }

